Consolidate arrival and departure presence events (#789)

[rtclauss]

Summary

• add Zeke arrival/departure emitter automations that own the shared home enter/leave and Bayesian on/off triggers
• move listed arrival/departure consumers to event triggers while preserving their independent modes, traces, and conditions
• keep state-only departure behavior for empty-house timestamp and vacuum start by filtering the emitted Bayesian source

Closes #789

Coverage / tests

• uv run --with pytest pytest
• uv run --with yamllint yamllint -d "{extends: relaxed, rules: {line-length: disable, empty-lines: disable, truthy: disable}}" configuration.yaml automations.yaml blueprints esphome packages zigbee2mqtt
• python3 /Users/rtclauss/.agents/skills/homeassistant-yaml-dry-verifier/scripts/verify_ha_yaml_dry.py packages/zone.yaml --strict
• python3 scripts/check_ha_python_support.py
• git diff --check

Validation note

• Home Assistant container check_config was attempted with a temporary CI-style config copy, but local Podman repeatedly stopped/reset its socket before the container could start. The initial run reached HA and failed only because direct worktree validation lacked CI placeholder secrets; the retried CI-style temp config could not launch due to Podman VM/socket failure.